# Using OpenLANE to Harden Your Design:

You can utilize the Makefile existing here in this directory to do that.

But, first you need to specify 3 things:
```bash
export OPENLANE_TAG=<the openlane tag/version you are using. This could be rc4 or rc5 based on when you cloned openlane and what branch you are using.>
export PDK_ROOT=<The location where the pdk is installed>
export OPENLANE_ROOT=<the absolute path to the cloned openlane directory>
```

**NOTE:** we recommend using openlane:rc4. Note the following [FAQ](https://github.com/efabless/openlane/wiki#why-am-i-getting-n-well-related-drc-violations-from-magic-when-using-the-latest-version-of-the-skywater-pdk).

If you don't have openlane already, then you can get it from [here](https://github.com/efabless/openlane). Alternatively, you can clone and build the openlane master through:
```bash
    make openlane
```

**NOTE:** We are developing caravel using openlane:rc5 which is the current develop branch. openlane:rc5 will be merged to master once the caravel chip is finalized.

Then, you have two options:
1. Create a macro for your design and harden it, then insert it into user_project_wrapper.

2. Flatten your design with the user_project_wrapper and harden them as one.


**NOTE:** The OpenLANE documentation should cover everything you might need to create your design. You can find that [here](https://github.com/efabless/openlane/blob/master/README.md).

## Option 1:

This could be done by creating a directory for your design here in this directory, and adding a configuration file for it under the same directory. You can follow the instructions given [here](https://github.com/efabless/openlane#adding-a-design) to generate an initial configuration file for your design, or you can start with the following:

```tcl
set script_dir [file dirname [file normalize [info script]]]

set ::env(DESIGN_NAME) <Your Design Name>

set ::env(DESIGN_IS_CORE) 0
set ::env(FP_PDN_CORE_RING) 0
set ::env(GLB_RT_MAXLAYER) 5

set ::env(VERILOG_FILES) "$script_dir/../../verilog/rtl/<Your RTL.v>"

set ::env(CLOCK_PORT) <Clock port name if it exists>
set ::env(CLOCK_PERIOD) <Desired clock period>
```

Then you can add them as you see fit to get the desired DRC/LVS clean outcome.

After that, run the following command:
```bash
make <your design directory name>
```

Then, follow the instructions given in Option 2.

**NOTE:** You might have other macros inside your design. In which case, you may need to have some special power configurations. This is covered [here](https://github.com/efabless/openlane/blob/develop/doc/hardening_macros.md#power-grid-pdn).

## Option 2:

1. Add your design to the RTL of the [user_project_wrapper](../verilog/rtl/user_project_wrapper.v).

2. Modify the configuration file [here](./user_project_wrapper/config.tcl) to include any extra files you may need. Make sure to change these accordingly:
```tcl
set ::env(CLOCK_NET) "mprj.clk"

set ::env(VERILOG_FILES) "\
	$script_dir/../../verilog/rtl/defines.v \
	$script_dir/../../verilog/rtl/user_project_wrapper.v"

set ::env(VERILOG_FILES_BLACKBOX) "\
	$script_dir/../../verilog/rtl/defines.v \
	$script_dir/../../verilog/rtl/user_proj_example.v"

set ::env(EXTRA_LEFS) "\
	$script_dir/../../lef/user_proj_example.lef"

set ::env(EXTRA_GDS_FILES) "\
	$script_dir/../../gds/user_proj_example.gds"
```
**NOTE:** Don't change the size or the pin order!

3. Remove this line `add_macro_placement mprj 1150 1700 N` from the interactive script [here](./user_project_wrapper/config.tcl) and replace it with the placement for your macro instances. Or, remove it entirely if you have no macros, along with this line `manual_macro_placement f`.

4. Run your design through the flow: `make user_project_wrapper`

5. Re-iterate until you have what you want.

6. Go back to the main [README.md](../README.md) and continue the process of boarding the chip.

**NOTE:** In both cases you might have other macros inside your design. In which case, you may need to have some special power configurations. This is covered [here](https://github.com/efabless/openlane/blob/develop/doc/hardening_macros.md#power-grid-pdn).

## Extra Pointers:


- The OpenLANE documentation should cover everything you might need to create your design. You can find that [here](https://github.com/efabless/openlane/blob/master/README.md).
- The OpenLANE [FAQs](https://github.com/efabless/openlane/wiki) can guide through your troubles.
- [Here](https://github.com/efabless/openlane/blob/master/configuration/README.md) you can find all the configurations and how to use them.
- [Here](https://github.com/efabless/openlane/blob/master/doc/advanced_readme.md) you can learn how to write an interactive script.
- [Here](https://github.com/efabless/openlane/blob/master/doc/OpenLANE_commands.md) you can find a full documentation for all OpenLANE commands.
- [This documentation](https://github.com/efabless/openlane/blob/master/regression_results/README.md) describes how to use the exploration script to achieve an LVS/DRC clean design.
- [This documentation](https://github.com/efabless/openlane/blob/develop/doc/hardening_macros.md) walks you through hardening a macro and all the decisions you should make. However, this is still on the develop branch of openlane and so may contain configuration references that are yet to come to master. For example, `FP_CONTEXT_DEF` and `FP_CONTEXT_DEF`.